PENDAHULUAN MIKROBIOLOGI KESEHATAN KLASI (1)

(1)

PENDAHULUAN MIKROBIOLOGI

KESEHATAN : KLASIFIKASI DAN

STRUKTUR SEL BAKTERI

(2)

TUJUAN

Setelah mempelajari materi pada hari ini

diharapkan anda dapat :

• Memahami klasifikasi mikroba dan taksonomi

bakteri

• Mampu membedakan antara sel prokariot

(bakteri) dengan eukariot

• Mampu memahami struktur sel bakteri

(3)

SUMBER PUSTAKA

• Mahon textbook of Diagnostic Microbiology

4th Ed.

(4)

(5)

(6)

ISTILAH

• Taksonomi

– Pengelompokan suatu organisme dalam suatu hierarki yang menggambarkan kedekatan hubungan di alam

• Klasifikasi

– Proses pengelompokan ke dalam suatu grup taksonomi

• Nomenklatur

– Penamaan suatu organisme menurut suatu konsensus internasional berdasarkan karakteristiknya

• Identifikasi

(7)

Taksonomi

Klasifikasi

Nomenklatur

Identifikasi

(8)

CONTOH

KLASIFI KASI

(9)

(10)

(11)

MICROBIAL WORLD

(12)

(13)

(14)

(15)

(16)

(17)

SIZE OF BACTERIA

external environment.

 Cocci: sphere, 1μ

 Bacilli: rods , 0.5-1 μ in width -3 μ in length

(18)

BACTERIAL STRUCTURE OVERVIEW

Particular structures :

capsule

flagella pili spore

Essential structures :

cell wall

cell membrane Cytoplasm

(19)

Gram +

Gram -

Cell wall

Cell (inner) membrane Outer membrane Ribosomes

Granule

Cell wall Nucleoid Cell membrane

Capsule

Flagellum

Pili

Gram, C. 1884. Ueber die isolirte Farbung der Schizomyceten in SchnittÄund

Trockenpraparaten. Fortschritte der Medicin_{, Vol. 2, pages 185-189.}

1884:

_{Christian Gram}

_{: First publication for the Gram}

(20)

Cell wall/Dinding sel

• Merupakan

bagian terluar,

dengan ketebalan 15-30nm dan

(21)

Cell wall

:

Lapisan Peptidoglycan

• Tersusun oleh N-acetyl glucosamine (NAG) dan N-acetylmuramic acid (NAM): ditemukan pada bakteri gram positif dan negatif

• Terdapat struktur tetrapeptide yang menempel pada NAM : menjadi tempat perlekatan AB pada bakteri

• Pada gram positif bakteri membentuk jalinan ross ridging : melindungi dari

(22)

(23)

Special components of Gram positive

cell wall

Teichoic acid

(24)

Special components of Gram

(25)

(26)

Hasil Pengecatan Gram

(27)

Hasil Pengecatan ZN:

(28)

Functions of Cell Wall

• Maintaining the cell's characteristic shape- the rigid wall compensates for the flexibility of the

phospholipid membrane and keeps the cell from assuming a spherical shape

• Countering the effects of osmotic pressure

• Providing attachment sites for bacteriophages

• Providing a rigid platform for surface appendages-

flagella, fimbriae, and pili all emanate from the wall and extend beyond it

• Play an essential role in cell division

• Be the sites of major antigenic determinants of the cell surface。

(29)

Wall-less forms of Bacteria

.

• When bacteria are treated with 1) enzymes that are lytic for the cell wall e.g. lysozyme or 2) antibiotics that interfere

with biosynthesis of peptidoglycan, wall-less bacteria are often produced.

• Usually these treatments generate non-viable organisms. Wall-less bacteria that can not replicate are referred to as spheroplasts (when an outer membrane is present) or

(30)

Cell

membrane

• Berperan dalam proses biosintesis DNA, polimerisasi dinding sel dan

e ra lipid elalui proses sele tive per ea ility u tuk tra spor

ke dalam sel

• Terjadi proses transpor elektron dan fosforilasi oksidatif

(31)

Cytoplasm

• Composed largely of water, together with proteins, nucleic acid, lipids and small amount of sugars and salts

• Ribosomes_{: numerous, 15-20nm in diameter with 70S;} distributed throughout the cytoplasm; sensitive to streptomycin and erythromycin site of protein synthesis

 Plasmids:_{extrachromosomal}

genetic elements

(32)

Plasmid

Plasmids are small，circular/line，

extrachromosomal，double-stranded DNA

molecules。They are capable of self-replication and

contain genes that confer some properties，such as

antibiotic resistance，virulence factors。Plasmids

are not essential for cellular survival.

Inclusions of

Bacteria

 Inclusions are

aggregates of various compounds that are normally involved in storing energy

reserves or building blocks for the cell. Inclusions accumilate when a cell is grown in the presence of excess nutrients and they are often

observed under

laboratory conditions.

granulose

(33)

Nucleus

• Lacking nuclear

membrane, absence of nucleoli, hence known as nucleic

(34)

Capsules and slime layers

• These are structures surrounding the outside of the cell envelope. They usually consist of polysaccharide; however, in certain bacilli they are composed of a polypeptide (polyglutamic acid). They are not essential to cell viability and some strains within a species will produce a capsule, whilst others do not. Capsules are often lost during in vitro_culture.

 Attachment

 Protection from

phagocytic engulfment.

 Resistance to drying.

 Depot for waste products.

 Reservoir for certain nutrients.

(35)

Flagella

Monotrichate/Amphitrichate/Lophotrichate/Peritrichate

 Identification of Bacteria

 Pathogenesis

 Motility of bacteria

Some bacterial species are mobile and possess locomotory organelles - flagella. Flagella consist of a number of proteins including flagellin

(36)

Pili

• Pili are hair-like projections of the cell , They are known to be receptors for certain bacterial viruses. Chemical nature is pilin

• Classification and Function

a. Common pili or fimbriae: fine , rigid numerous, related to bacterial adhesion

b. Sex pili: longer and coarser, only 1-4, related to

(37)

Pilli vs Flagel

(38)

(39)

Endospores

(spores)

• Dormant cell

• Resistant to adverse

conditions

- high temperatures - organic solvents

• Produced when starved

• Contain calcium dipicolinate

DPA, Dipicolinic acid

• Bacillus and Clostridium

 Identification of Bacteria

 Pathogenesis

(40)

(41)